The aforementioned HB 127 would move the primary from the first Tuesday after the first Monday in February to the first Tuesday after the first Monday in April. However, the bill (SB 177) introduced by state Senator Eric Schmitt (R-15th, St. Louis) would push the primary back only a month to March. That makes the legislation most like the majority of legislation addressing the primary date during the 2011 legislative session.
A couple of notes:
1) Again, the Missouri presidential primary is currently scheduled for February. That will not be compliant with either national party's ultimate delegate selection rules. The Show-Me state, then, is the rare state that has to make some change in its date to comply with those rules. The other potential early February states have other options. Presumably Missouri would too (at least on the Republican side). The Missouri Republican Party opted for a March caucus to avert sanctions from the RNC and Show-Me state Democrats were granted a waiver because the date of the primary was determined by the Republicans in the majority in both chambers of the General Assembly. The decision on the part of the Democratic Rules and Bylaws Committee was made easier by virtue of the fact that President Obama was running unopposed for the Democratic nomination. That condition will not exist in 2016. In other words, if the primary is not moved back, the Democratic Party in the state would have a tougher case to make before the RBC.
2) Traditionally, Missouri Republicans have allocated their delegates in a winner-take-all fashion since the primary format was reintroduced for the 2004 cycle. Only the House bill would allow for that practice to continue. An April primary date -- as called for in the House version of the bill -- would place the Missouri presidential primary out of the March (and earlier) proportional window called for in the RNC delegate selection rules and allow the state GOP to maintain the winner-take-all allocation. Alternatively, if the March Senate bill passes both chambers and is signed into law, the state party would have to alter its delegate selection plan in some way. This is only a concern among Republicans in the state since the DNC mandates a proportional allocation of delegates. But this may be some cause for conflict between the chambers of a Missouri General Assembly controlled by Republicans.
...and if you followed the state legislative effort/inability to move the Missouri primary in 2011, this is potentially some cause for concern.